3307twf.d〇c/〇Q6 A7 B7 五、發明説明（I ) 本發明是有關於一種積體電路的製造方法，且特別是 有ϋ於一種用以降低場氧化層厚度之場隔離區之結構及其 製造方法。 元件的場隔離區係用以防止載子（Carrier)通過基底而 在相鄰的元件間移動之用。傳統上，場隔離區係形成於稠 密的半導體電路，比如是動態隨機存取記憶體(DRAM)中 相鄰的場效電晶體（Field Effect Transistor，FET)間，藉以 減少由場效電晶體產生的漏電流(Leakage)現象。典型形成 場隔離區的方法係採用局部區域氧化技術(L0C0S)。由於 局部區域氧化技術的日趨成熟，因此在半導體製程中可藉 由此技術，以較低的成本獲得可靠度高且有效之場隔離結 構1/。 第1A圖至第1D圖爲習知一種以局部區域氧化法製作 場隔離區的流程剖面圖。首先，請參照第1A圖，在所提 供的矽基底1〇〇上形成一層墊氧化層(pad〇xide)i〇2,然後， 再於墊氧化層102上形成一層氮化矽層104。典型形成墊 氧化層102的方法係以熱氧化的方式；而形成氮化矽層1〇4 的方法則例如爲低壓化學氣相沈積法(LPCVD)。 接著’請參照第1B圖，以習知的方法定義氮化砂層 104 ’以定義元件的隔離區域。典型的方法，係在氮化矽 層104上形成一層光阻層(未繪示），然後再經由微影技術 將光阻層圖案化，並藉由蝕刻技術，將部份的氮化矽層104 去除，以定義元件的隔離區域106與主動區域107。最後， 再將光阻層剝除。 3 -------,----裝------訂------Μ {請先閲讀背面之注項再填寫本頁) 經米部屮头ii.準而只T;消资合竹，·5-卬^ 本紙張尺度ίΐ州中阐國家栋準（CNS ) A4規格Ϊ210Χ297公釐） ~ 3307twf.doc/006 A7 B7 五、發明説明（i) 其參照第1C圖，以濕式氧化法，在含有水氣 的高溫進行場氧化層120的成長，以形成元件之 場隔離區於氮化矽層104在高溫下對水分子與氧 氣的擴散具阻擋能力，因此，除了少部份靠近氮 化矽層角落的@底100外，在氮化矽層104所覆蓋的矽 基底100表面並不會有生成氧化矽。而少部份靠近氮化矽 層104角落的矽基底，以及未被氮化矽層1〇4所覆蓋的矽 基底之表面，則被氧化成一層場氧化層120，以構成場隔 離區106a。 然後，請參照第1D圖，以習知的方法將氮化矽層104 剝除。典型的方法係以經加熱的磷酸(Phosphoric Acid)，或 以含氟的氣體電漿來執行氮化矽層104的剝除。 最後，請參照第1C圖，在上述的方法中，由於水分 子與氧氣對罩幕層104角落的部份，依然有能力進行水平 方向的擴散或滲透，因此位於氮化矽層104角落的矽基底 100，仍會產生不同程度的氧化，而使所形成之場隔離區 106a出現鳥嘴區l〇8(Bird’s Beak)»其中，場隔離區106a 的非鳥嘴區108’中，靠近鳥嘴區108的部份厚度漸薄，未 能深入基底100，而降低了電性隔離的效果，因此習知方 法須製造夠厚的場氧化層120,才能達到電性隔離的效果， 然此作法將不利於場區之平坦化。除此之外，鳥嘴區108 將減少元件主動區的有效區域(Effective Area)，使半導體 元件朝向高度積集化的目標受到限制，將不利於0.5μιη 以下之製程。 4 本紙張尺度適州中囷國家榡半（CNS ) Α4规格（210X297公釐）3307twf.d〇c / 〇Q6 A7 B7 V. Description of the Invention (I) The present invention relates to a method for manufacturing an integrated circuit, and particularly to a structure of a field isolation region for reducing the thickness of a field oxide layer. And its manufacturing method. The device's field isolation region is used to prevent carriers from moving through adjacent substrates between adjacent components. Traditionally, field isolation regions are formed in dense semiconductor circuits, such as between field effect transistors (FETs) adjacent to each other in dynamic random access memory (DRAM), thereby reducing the generation of field effect transistors. Leakage phenomenon. A typical method for forming a field isolation region is to use a local area oxidation technique (LOC0S). Due to the maturity of local area oxidation technology, this technology can be used in semiconductor processes to obtain highly reliable and effective field isolation structures 1 / at a lower cost. Figures 1A to 1D are cross-sectional views of a conventional process for producing a field isolation region by a local area oxidation method. First, referring to FIG. 1A, a pad oxide layer 102 is formed on the provided silicon substrate 100, and then a silicon nitride layer 104 is formed on the pad oxide layer 102. A typical method for forming the pad oxide layer 102 is thermal oxidation. A method for forming the silicon nitride layer 104 is, for example, a low pressure chemical vapor deposition (LPCVD) method. Next, please refer to FIG. 1B, and define a nitrided sand layer 104 'by a conventional method to define an isolation region of the device. A typical method is to form a photoresist layer (not shown) on the silicon nitride layer 104, and then pattern the photoresist layer by lithography, and then use etching technology to partly form the silicon nitride layer. 104 is removed to define the isolation region 106 and the active region 107 of the component. Finally, the photoresist layer is peeled off. 3 -------, ---- install ------ order ------ Μ (Please read the note on the back before filling out this page) Only T; Consumption and Combination of Bamboos, · 5-ΐ ^ The paper size is ΐZhongzhou National Building Standard (CNS) A4 Specification Ϊ210 × 297 mm) ~ 3307twf.doc / 006 A7 B7 V. Description of the Invention (i) It refers to the Figure 1C. The wet oxidation method is used to grow the field oxide layer 120 at a high temperature containing water vapor to form a field isolation region of the element. The silicon nitride layer 104 has a barrier ability to diffuse water molecules and oxygen at high temperatures. Therefore, there is no silicon oxide generated on the surface of the silicon substrate 100 covered by the silicon nitride layer 104, except for a small portion of the bottom 100 near the corner of the silicon nitride layer. A small portion of the silicon substrate near the corner of the silicon nitride layer 104 and the surface of the silicon substrate not covered by the silicon nitride layer 104 are oxidized into a field oxide layer 120 to form a field isolation region 106a. Then, referring to FIG. 1D, the silicon nitride layer 104 is stripped in a conventional manner. A typical method is to perform the stripping of the silicon nitride layer 104 with a heated phosphoric acid or a fluorine-containing gas plasma. Finally, please refer to FIG. 1C. In the above method, because water molecules and oxygen still have the ability to diffuse or penetrate horizontally in the corners of the mask layer 104, the silicon located at the corners of the silicon nitride layer 104 The substrate 100 will still produce different degrees of oxidation, so that the formed field isolation region 106a appears as a bird's beak region 108 (Bird's Beak) », among which the non-bird's beak region 108 'of the field isolation region 106a is close to the bird's beak. The thickness of the portion of the region 108 is gradually thinner, failing to penetrate into the substrate 100, and the effect of electrical isolation is reduced. Therefore, the conventional method must produce a sufficiently thick field oxide layer 120 to achieve the effect of electrical isolation. Not conducive to the planarization of the field area. In addition, the bird's beak region 108 will reduce the effective area of the active area of the device, which will limit the semiconductor device toward the goal of high accumulation, which will be detrimental to the process below 0.5 μιη. 4 This paper is in the middle of the state of Central China (CNS) Α4 size (210X297 mm)
In 1 I —1 -I-I - - - I - _I — --. (請先閲讀背面之注意事項再填寫本頁In 1 I —1 -I-I---I-_I —-. (Please read the notes on the back before filling this page
、1T 33〇7twf.d〇c/006 A7 B7 經"•部中央"-羋而以-7'消炝合竹"印絮 五、發明説明（>) 因此本發明的目的就是在提供一種場隔離區之構造， 可以較薄的場氧化層，達到電性隔離的效果。而且，除了 有利於場區之平坦化之外，較薄的場氧化層之鳥嘴區長度 也較短，可增加元件主動區的有效區域，有利於提高元件 的積集度。 此外’本發明的另一目的是提供一種場隔離區的製造 方法，藉以製造上述之場隔離區的結構，以完成較薄的場 氧化層。 根據本發明之上述目的，提出一種場隔離區之結構及 其製造方法，此製造方法簡述如下··首先在一基底上覆蓋 —由墊氧化層和氮化矽層組成的罩幕層，並於罩幕層中形 成一開口，以露出部份基底；接著在此部份基底之周圍形 成一溝渠；而後氧化此部份基底之表面，以形成一場氧化 層；隨後去除氮化矽層’即完成場隔離區之製作。依此方 法製造之場氧化層在非鳥嘴區中，靠近鳥嘴區的周圍部份 有一凹陷區，且此凹陷區的底部深於場氧化層的其他部 位。 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂，下文特舉一較佳實施例，並配合所附圖式，作詳 細說明如下： 圖式之簡單說明： 第1A圖至第1D圖爲習知一種以局部區域氧化法製作 場隔離區的流程剖面圖；以及 第2A圖至第2E圖所不’其繪示依照本發明一較佳實 5 本紙張尺度適州中國國家榇準（CNS ) A4規格（210X297公釐） (請先閲讀背面之注意事項再域寫本頁) -裝. 訂 3307twf.doc/006 A7 B7 五'發明説明（¥) 施例的一種場隔離區之結構及其製造方法之流程剖面圖； 圖式之標記說明： 100，200 ··基底 102，202 :墊氧化層 104，204 :氮化矽層 106，206 :隔離區域 106a，206a :場隔離區 107 :主動區 108，208 :鳥嘴區 120，220 :場氧化層 108’，208’ ：非鳥嘴區 209:第一開口 210 :第二開口 222 :凹陷區 實施例 首先，請參照第2A圖，在所提供的矽基底200上形 成一層墊氧化層(Pad Oxide)202，然後，再於墊氧化層202 上形成一層氮化矽層204。典型形成墊氧化層202的方法 係以熱氧化的方式；而形成氮化矽層204的方法則例如爲 低壓化學氣相沈積法(LPCVD)。 接著，請參照第2B圖，以習知的方法定義氮化矽層204 與墊氧化層202，以定義元件的隔離區域。典型的方法， 係在氮化砂層204上形成一層光阻層(未繪示），然後再經 由微影技術將光阻層圖案化，並藉由蝕刻技術，將部份的 6 本紙張尺度適州t囷國家標準（CNS ) A4規格（210X297公釐） -----------------訂------¼ /V ' \L· C铕先聞讀背面之注f項再填对本頁，> 經"·•部十头打準而只·τ消贽合作.衫印掣 3307twf.doc/006 A 7 _B7 ____ 五、發明说明（5Ί 氮化矽層204與墊氧化層202去除’以形成開口 209 ’露 出部份之基底200，作爲元件的隔離區域206。最後’再 將光阻層剝除° 其後，請參照第2C圖，於暴露出的隔離區域206之 基底周圍形成溝渠210，使溝渠210之基底表面略低於其 他部份之基底表面。形成溝渠210之方法例如在基底200 上形成一層光阻層（未繪示），然後再經由微影技術將光阻 層圖案化，並以乾蝕刻的方式，將部份矽基底200去除’ 以形成溝渠210。 '其後\請參照第2D圖，以濕式氧化法’在含有水氣 的高溫進行場氧化層220的成長’以形成元件之 場隔離氮化矽層204在高溫下對水分子與氧 氣的擴散具阻擋能力，因此，除了少部份靠近氮 化矽層角落的砍 1底200外，在氮化矽層204所覆蓋的矽 基底200表面並不會有生成氧化矽。而少部份靠近氮化矽 層204角落的矽基底，以及未被氮化矽層204所覆蓋的矽 基底之表面，則被氧化成一層場氧化層220，以^_隔 離區206a。與習知場氧化層不同的是，此場氧化中 央的非鳥嘴區208’中，靠近鳥嘴區208的部份具有陷 區222 ’此凹陷區222的底部深於場氧化層220的!^部 位，可對後續製造之元件作出較佳的電性隔離。 然後，請參照第2E圖，以習知的方法將氮化矽層204 剝除。典型的方法係以經加熱的磷酸(Phosphoric Acid)，或 以含氟的氣體電漿來執行氮化矽層204的剝除。 7 (請先閲讀背面之注意事項再填寫本页) 'ί装. 、1Τ 本紙張尺度適/彳】中國國家樣率（CNS } Α4現格（210X297公釐） 3307twf.doc/006 A7 B7 五、發明説明（6) 由上述本發明較佳實施例可知，本發明之特徵在於所 製造之場隔離區具有一形狀特殊之場氧化層，其特殊之處 在於非鳥嘴區中，靠近鳥嘴區的周圍部份有一凹陷區’且 此凹陷區的底部深於場氧化層的其他部位，較能深入基 底，故而可使場氧化層的電性隔離效果，優於習知局部區 域氧化法所形成的場氧化層。由於電性隔離效果的提高， 本發明之場氧化層厚度可較習知所製造者爲薄，不但利於 後續製程之平坦化，其鳥嘴區長度也可隨之縮短，增加主 動區的有效區域。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作各種之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 (請先閲讀背面之注^^項再填寫本i ) i τ1T 33〇7twf.d〇c / 006 A7 B7 The "Ministry of the Central Government"-and -7 'to eliminate the combined bamboo " Printed V. Description of the invention (>) Therefore, the purpose of the present invention is By providing a structure of a field isolation region, a thinner field oxide layer can be used to achieve the effect of electrical isolation. In addition, in addition to facilitating the planarization of the field region, the length of the bird's beak region of the thinner field oxide layer is also shorter, which can increase the effective area of the active region of the element, which is conducive to increasing the accumulation of the element. In addition, another object of the present invention is to provide a method for manufacturing a field isolation region, so as to manufacture the structure of the above-mentioned field isolation region to complete a thinner field oxide layer. According to the above purpose of the present invention, a structure of a field isolation region and a manufacturing method thereof are proposed. The manufacturing method is briefly described as follows: firstly, a substrate is covered with a mask layer consisting of a pad oxide layer and a silicon nitride layer, and An opening is formed in the mask layer to expose a part of the substrate; then a trench is formed around this part of the substrate; and then the surface of this part of the substrate is oxidized to form a field oxide layer; then the silicon nitride layer is removed. Complete the production of the quarantine area. The field oxide layer manufactured in this way has a recessed area in the non-bird's beak area, and the surrounding part near the bird's beak area, and the bottom of the recessed area is deeper than other parts of the field oxide layer. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is described below in detail with the accompanying drawings as follows: Brief description of the drawings: FIG. 1A Figures 1 to 1D are cross-sectional views of a conventional process for producing a field isolation region by a local area oxidation method; and Figures 2A to 2E are not shown, which illustrate a preferred embodiment of the present invention. National Standards (CNS) A4 (210X297 mm) (Please read the notes on the back before writing this page)-Book. Order 3307twf.doc / 006 A7 B7 Five 'Invention Description (¥) A Field of Example The structure of the isolation region and the flow cross-sectional view of the manufacturing method; The marks of the drawings explain: 100, 200 · · substrate 102, 202: pad oxide layer 104, 204: silicon nitride layer 106, 206: isolation regions 106a, 206a: Field isolation area 107: active area 108, 208: bird's beak area 120, 220: field oxide layer 108 ', 208': non-bird's beak area 209: first opening 210: second opening 222: recessed area embodiment First, please Referring to FIG. 2A, a pad oxide layer is formed on the provided silicon substrate 200. (Pad Oxide) 202, and then a silicon nitride layer 204 is formed on the pad oxide layer 202. A typical method for forming the pad oxide layer 202 is thermal oxidation; a method for forming the silicon nitride layer 204 is, for example, a low pressure chemical vapor deposition (LPCVD) method. Next, referring to FIG. 2B, a conventional method is used to define the silicon nitride layer 204 and the pad oxide layer 202 to define the isolation region of the device. A typical method is to form a photoresist layer (not shown) on the nitrided sand layer 204, and then pattern the photoresist layer by lithography technology, and then use etching technology to adapt a part of 6 papers to a suitable size. State t 囷 National Standard (CNS) A4 specification (210X297 mm) ----------------- Order ------ ¼ / V '\ L · C 铕Read the note f on the back and then fill in this page, > After the Ministry of Justice has made ten heads and only τ eliminates cooperation. Shirt printing button 3307twf.doc / 006 A 7 _B7 ____ 5. Description of the invention (5Ί The silicon nitride layer 204 and the pad oxide layer 202 are removed to form an opening 209 and the exposed portion of the substrate 200 is used as an isolation region 206 of the device. Finally, the photoresist layer is peeled off. ° Then, please refer to FIG. 2C, A trench 210 is formed around the substrate of the exposed isolation region 206, so that the substrate surface of the trench 210 is slightly lower than other substrate surfaces. The method of forming the trench 210 is, for example, forming a photoresist layer on the substrate 200 (not shown) Then, the photoresist layer is patterned by lithography technology, and a portion of the silicon substrate 200 is removed by dry etching to form a trench 210. 'Afterwards, please Referring to FIG. 2D, the wet oxidation method is used to 'grow the field oxide layer 220 at a high temperature containing water vapor' to form a field isolating silicon nitride layer 204, which has a barrier ability to diffuse water molecules and oxygen at high temperatures. Therefore, except for a small portion of the substrate 200 near the corner of the silicon nitride layer, no silicon oxide is generated on the surface of the silicon substrate 200 covered by the silicon nitride layer 204. A small portion is near the silicon nitride layer 204 The corner silicon substrate and the surface of the silicon substrate not covered by the silicon nitride layer 204 are oxidized into a field oxide layer 220 to isolate the region 206a. Unlike the conventional field oxide layer, this field In the non-bird's beak region 208 'of the oxidation center, a portion near the bird's beak region 208 has a recessed region 222' The bottom of this recessed region 222 is deeper than the! ^ Portion of the field oxide layer 220, which can make better components for subsequent manufacturing Then, please refer to Figure 2E to strip the silicon nitride layer 204 in a conventional manner. A typical method is to use heated phosphoric acid or a gas plasma containing fluorine. Perform stripping of the silicon nitride layer 204. 7 (Please read the note on the back first Please fill in this page for more information) 'ίpack., 1T The paper size is suitable / 彳] Chinese national sample rate (CNS) Α4 is now (210X297 mm) 3307twf.doc / 006 A7 B7 V. Description of the invention (6) From the above As can be known from the preferred embodiment of the present invention, the present invention is characterized in that the manufactured field isolation region has a field oxide layer with a special shape, which is special in the non-bird's beak area, and a recessed area near the bird's beak area. 'And the bottom of this recessed area is deeper than other parts of the field oxide layer and can penetrate deeper into the substrate, so the electrical isolation effect of the field oxide layer is better than that of the field oxide layer formed by the conventional local area oxidation method. Due to the improvement of the electrical isolation effect, the thickness of the field oxide layer of the present invention can be thinner than that of a conventional manufacturer. . Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. (Please read the note ^^ on the back before filling in this i) i τ